The present invention provides improvements in the power steering gear disclosed in my U.S. Pat. No. 4,008,063. This prior patent, among features provides for improved piston reversibility due to reduced friction between the piston and the cylinder of the unit, as a result of utilization of unique fluid bearings. This fluidized bearing concept is an improvement over my earlier U.S. Pat. No. 3,092,083, which discloses and claims the basic power steering gear with a distributing valve in the piston.
The invention of the prior improvement U.S. Pat. No. 4,088,063 provides a substantial net power output increase to the steering gear. However, the prior improvement does not provide improved responsiveness, i.e., reduced steering wheel movement to provide the same power output of the steering gear over the range of operation of the steering gear.
Basically, it has been found that the desired improved responsiveness may be obtained through the use of an increased spring force to center the valve within the piston. It has been discovered that the increased spring force is ideally provided by doubling the spring rate constant of the washer springs at the ends of the valve.